Lens and bjbflector pob adding machines



Sept. 21 ,1920.

G. DuKHAR-r LENS AND REFLEGTOR FOR ADD'ING MACHINES Filed Feb. 18, 1925 akku um* Patented seat. 21, i926.

, UNITED STATES GRAHAM DKEHART, F POR'LAND, OREGON.

LENS AND BEFL'ECTOB FOR ADDING MACHINES.

Application led February 18, 1925. Serial No. 9,910.

This invention relates particularly to addling machines such as are 'used at banks for bookkeeping and preparing statements of acounts. 5 The first object of this invention is to provide a specialforin of lens which will have the properties of a prism and which will present an image of a figure normally held at an angle to the line of sight so that it will appear'to be perpendicular to the line of sight.

The second object is to equalize the focal planev sufficient-ly to overcome the present difference in distance between the eye of the operator of an adding machine and objects between which the focus is constantly changing, that is-the checks or other data from which the values are being transferred to the keys and the platen of the adding machine which carries a statement whose last balnce it is necessary for the operator to rea The third object is to increase the efficiency ofthe operator by greatly reducing the eye strain by increasing his capacity for work with less fatigue, and reducing the liability for errors with the attendantloss of time required to correct such errors.

The fourth object is to eliminate the distortion of figures in the balance 'column on the statement placed on the platen.

The fifth object is the more economical use of statement forms by permitting the vertical spacings to more nearly approach the line finder ,and thereby increasing the num-ber of lines which maybe entered on a given length of statement. y

The sixth object is to Jeconox'nize on the amount of light consumed, where artificial light is employed, and to do so with the appreciable decrease in eye strain .on the part of the operator.

The seventh object is to combine a reflector with the lens above 'mentioned in order to i enable the operator to avail himself of suiiicient light to easily read amounts under the lens without the necessity of overillumination at any point, with its attendant glare on the keys and shiny portions of the adding machine.

These results are accomplished in the manner set forth in the following specification as illustrated in the accompanying drawing, inBwhich: f'

i ure 1 is a ragmenta perspective viewgof the -rght side of an aing machine showing the device in place. Figure 2 is a side elevatlon of the device showing the approximate lines of refraction, the relative position of the eye of the operator, and the relation which this device bears to the platen of the adding machine. F igure 3 is a front elevation'of Figure 2 of which Figure 4 is a4 plan. Figure 5 is a view showing the ap-l pearance of-an ordinary typewritten charac 65 ter on a statement which has been placed on the platen, when viewed-by the operator in his normal position, as indicated in Figure 2. vFigure 6 is aview showing the same character under the same conditions, but whose image has been corrected by the device about to be described.

Similar numbers of reference refer to the same 'partsthroughout the several views. Referring more particularly to the draw? ing, the device is shown in connection with an'ordinary Vaddin machine 10 lof the bookkeeping type provided with the usual keys 11, platen 12 and line finder 13 having a curled end 14 on which this device is mounted. A statement 15 is indicated on the platen 12 and a check 16'is also indicated, to better illustrate the use of the invention and the distances between which the eye 17 must be focused. 85 Turning now to the device itself it will be seen to consist of a U-shaped frame comprising a somewhat horizontal lower p0rtionv y18 and vertical arms 19 on whoseupper ends are pivotally mounted the holders 20 on the screws 21 by means of thenuts 22. Between the holders 20 is placed a prismatic lens 23v whose upper side is sufficiently curved to providev the desired amount of magnification, and -Whose under sidev 24 forms a prism with its curved side 25, thereby overcoming the foreshortening of the figures on the statement 15, owingto the elevated position ofy the eye 17.

Formed on the member 18 is an upright 100 vtongue 26 having an outturned ear 27 which is adapted to curl around the end 14 of the line finder 13. ,Also formed on the .tongue 26 is a downturned ear 28 which hooks over the end 29 .of the line finder 13.

Formed integral with the member 18, or attached thereto, is a depending arm .30 which supports a reector 31. T e a'rm 30 is preferably of Va pliable material adapted to permit same to be bent or twisted so that the reflector 31 will reflect the best light possible above the statement sheet on the platen in thebalance column of figures when said platen is in its furtherniost right hand position, and preferably reflect this light between the members 19 under the lens 23.

In Figures 5 and 6 is illustrated the images or likenesses of a balance figure with and without using this device. In Figure 5 it will be observed that lthe upper portion of the numeral 8 is large and the lower portion is small, and both are less than their proportional height. In *Figure 6 it will be observed that the upper portion of the 8 is practically the same width as in-Figure 5, but the-lower portion is much larger, and both the upper and lower portions are correspondingly taller, making the reading of same a comparativel eas mattei', notwithstanding the fact t at t e figures on the statement on the platen are considerably flu'- ther removed than are the figures on the check 16, or other paper from which values are being taken. In Figure 2 can be seen the approximate lines of refraction and the reason why a corrected image is necessary on machines of this type to overcome the enormous aggregate of ,eye strain usually undergone by operators of this type of adding machine.

y, In Figure 1 the. line 32 represents the focal distance when reading values on the platen, and line 33 the much shorter distance from the eye 17 to a check usually under the left hand of the operator.

The operation of the device is as follows Having mounted the device on the end of the line finder, as illustrated, the next step is to adjust the angular position of the l'ens 23 under the control of the nuts 22, the tall operator naturally requiring a different angle than ashorter operator. Instead of the operator seeing a group of characters, as illustrated in Figure 5, he now sees them as shown in Figure 6, and since they are much enlarged over the actual figures on the statement there need be no change of focus when shifting the eyes from the platen to the check..

In case the illumination in insuiiicient to make the reading of figures through this lens a matter of Aextreme ease, available light, either natural or artificial may be directed to the area-under the lens by properly bending the arm of the reflector 31. This will enable. the operator to avoid the use of over illumination of other parts of the machine in order to secure sufficient illumination of the remote characters under the lens. p

It will understood, of course, that the operator is4 interested in reading the value under the lens only immediately following the insertion of the statement in the machine, and at no other time. It is for this reason that the device is made stationary with relation to the platen.

In many instan the 11S@ 0f the IGQCOF may be dispensed with, and in other instances is may be desirable to incorporate the lens holder with the line finder itself, use having been made of the present line finder merely because of its convenience in attach ing the device to the present adding machine` without the necessity of altering the machine or the employment of more than ordinary skill. However, by employing this type of holder, which includes the ears 27 and 28, it is evident that the device cannot inove in any direction except upwardly, against which movement it is l held by gravity.

. Attention is drawn to my United States Patent No. 1,528,198, over which this device is an improvement. V

I am aware that various forms of reec tors have been employed for adding machines, typewriters, etc. in the past, I therefore do not claim such devices broadly but I do intend to cover all such forms of my device as fall fairly within the appended claims.

I claim:

1. In an adding machine, the combination of a platen; a line finder in front of said platen; and a prismatic lens mounted above and in front of said line finder.

2. The combination of a cylindrical platen with a line iinder in front of said platen; a prismatic lens adapted to correct distortion of characters on a paper on said platen above said line finder; a frame for supporting said lens; and neans for adjusting the position of said lens with relation to said line iinder.

3. The combination of a cylindrical platen; a line finder mounted near the horizontal center of said platen; and a prismaticv magnifying lens mounted in front of and above said line finder adapted to rectify and enlarge images of characters appearing just above said line finder for an eye above and in front of said lens.

4. 'Ihe combination of a line finder adapted to be mounted in front of a platen of an adding machine with a U-shaped bracket supported near the outer end of said line inder; a prismatic lens held between the open ends of said bracket, said lens being capable of .adjustment on an vaxis parallel with said platen and so shapedi'that the image of a character used upon` said line finder will be magnified and corrected foi` distortion for an eye positioned above and in front of said lens.

5. In an adding machine, the combination of a line finder; a U-shaped frame mounted in front-of said line finder; a prismatc lens pivotally mounted between the open ends of said frame; and a. reflector adjustably mounted in front of said frame adapted to reflectlight under said lens above said line finder.

6, In an adding machine, the combination of a U-shaped frame having anv upwardly extending arm formed-on its lower side, said arm having a laterally and backwardly turning ear and a downwardly and backwardly turning ear formed at its top end, both of said ears forming means for attaching said frame to the curved end 4of a line finder of an adding machine; a prismatic lens pivotally mounted between the upper end of said frame, saidpivots having locking nuts placed thereon, said lens having its upper` face slightly convex and having its lower face forming an angle with Vthe chord of said curved side.

7. In an adding machine, the combination ,of a U-shaped frame having an upwardly extending arm formed on its. lower side, said arm having means for` attaching same to the line finder. of an adding machine; a prismatic lens pivotally mounted between the upper ends of said frame; nuts for clamping said lens in a desired position on its pivots; and a reflector supported b v said U- shaped frame adapted to reflect light through "said frame under said lens in a manner to illuminate the space over the vright hand end of said line finder within the focus of said lens.

Gann-IMMv DUKEHART. 

